The present invention relates to a functional food packaging material and a method for making the same, and more particularly to a synthetic resin-based food packaging material which includes calcium carbonate powder coated with zinc oxide, boehmite powder coated with titanium dioxide, hydroxyapatite (Ca10(PO4)6(OH)2) powder coated with iron, fine natural mineral powder, and charcoal powder particles, and thus has improved antimicrobial activity so as to improve the storage stability of food, and to a method for making the same.
With an increase in income levels and improvement in the living standard, national interest in food quality is increasing. Furthermore, as the consumption of environmentally friendly agricultural products and cold-stored meat increases rapidly, the need is increasing for functional packaging materials that are capable of maintaining the freshness of agricultural produces and preventing the oxidation of food during distribution in order to improve national health.
Technologies for preventing food spoilage include a functional packaging technology for maintaining freshness, which is embodied by blocking oxygen that causes changes in food quality, or adsorbing and decomposing the hormone ethylene that causes spoilage by accelerating the maturation of agricultural products or plants, or controlling the content of water that causes food deterioration, or adding antibacterial ad antifungal substances.
Methods for producing domestic and foreign food packaging materials aiming to increase the maintenance period of freshness of contents in the packaging materials are largely classified into two methods: an addition method in which a freshness-maintaining substance for controlling ethylene gas is added during manufacturing of packaging materials; and a perforation method in which fine holes are formed during manufacturing of packaging materials in order to adjust the amounts of carbon dioxide and oxide in the packaging materials to suitable levels.
Typical methods that are used in studies on functional packaging materials include methods of releasing or adsorbing specific gas to control the concentration of the gas or of adding antimicrobial substances, antioxidants or anti-fogging agents. In recent years, in addition to this functionality in the sense of food storage, the concept of consumer convenience, quality control and environmental protection has been introduced, and thus new packaging technologies, including an easy-to-peel package, a time-temperature indicator (TTI) that cumulatively indicates the time-temperature history, an oxygen indicator, and the like, have been developed mainly in advanced countries, and interest in packaging materials has increased.
Packaging materials including freshness-maintaining agents, developed in domestic and foreign countries, have been partially commercialized using charcoal or chitosan. However, these packaging materials, in fact, place emphasis on antimicrobial activity, and do not greatly differ from conventional products with respect to the effect of maintaining freshness, and thus are insufficient for commercialization in terms of maintenance of freshness. In particular, most packaging material products produced in Korea have been produced in small amounts by use of technologies developed in Japan and the like, rather than technologies developed in Korea.
In foreign countries, freshness-maintaining packaging technologies have been directly commercialized and are being marketed as products. Packaging materials produced by the addition method include Green Bag (USA) and Aisaika (Japan), and packaging materials produced by the perforation method include P-Plus (Japan) and Xtend (Stepac, Israel).
Green Bag (USA) and Aisaika have been imported and marketed in Korea, but the recognition thereof is not high due to their high costs and the like. P-Plus (Japan) has also been imported into Korea, but the sales volume thereof is not high due to the limitation of the perforation method and its high costs. Xtend is expected to be imported into Korea, but the use thereof for general purposes is limited due to the limitation of the perforation method.
In an attempt to solve such problems, Korean Patent No. 10-0949531 filed by the present inventors discloses a packaging material including powdery particles that contain natural mineral materials and charcoal. This packaging material is excellent in terms of food storage stability, but has a problem in that, because most of the powdery particles added are surrounded by synthetic resin, the powdery particles should be added in amounts larger than actually required. However, when the amount of powdery particles added increases, there are problems in that the formability of the packaging material is adversely affected and the transparency of the packaging material can be reduced.
In addition, in order to further improve the storage stability of food, an antioxidant function to prevent food oxidation (oxidative rancidity) needs to be enhanced. As used herein, the term “rancidity” refers to a phenomenon in which the oxidation of food by oxygen in air deteriorates the taste and color of the food and causes an off-flavor, thereby changing the appearance of the food. Rancidity deteriorates the quality of food, destroys the nutrients of food, and may cause oncogenes. Thus, in order to improve the storage stability of food, it is required to prevent rancidity by removing oxygen from the inside of food packaging materials to the highest possible extent. In the prior art, in order to remove oxygen from the inside of food packaging materials, a method was mainly used in which a deoxidizing agent or an oxygen-absorbing agent is prepared separately and placed in a packaging box or a packaging container. However, this method has problems in that it uses a complicated process and when it is applied to agricultural products, meat, fishes or shells, which have high water contents, the deoxidizing agent may flow out to contaminate the foods.
In the case of some foods, particularly meat and fish, the freshness of the foods is reduced by bacterial growth. In order to prevent this reduction in freshness, it is required to develop technology related to a functional packaging material having enhanced antimicrobial activity in addition to the effect of maintaining freshness.